Useful Life of Permeation Devices

Abstract

Sheath systems 20, 40 are attached to the chemical emitting ends of permeation devices or permeation tubes 10, 30 to retard the release of stored chemicals before the intended use of the improved permeation devices. Sheath systems may be made of polyolefin material, Fluorinated ethylene propylene (FEP) resin or other material in a heat shrink configuration wherein heat is applied to contract, shrink wrap or otherwise secure the sheath to a permeation tube. At the time of intended use, the sheath assembly may be removed without damage to the permeation device.

What is claimed is: 
     
         1 . A system to improve the useful life of a permeation tube, the system comprising:
 a) a sheath fastened to a chemical emitting end of a permeation tube.   
     
     
         2 . The system of  claim 1  wherein the sheath comprises a body, distal shoulder and distal cap. 
     
     
         3 . The system of  claim 2  wherein the sheath further comprises a proximal shoulder. 
     
     
         4 . The system of  claim 3  wherein the permeation tube contains Ammonia Crystal. 
     
     
         5 . The system of  claim 3  wherein the sheath comprises polyolefin. 
     
     
         6 . A system to improve the useful life of a permeation tube, the system comprising a circular sheath attached to a chemical emitting end of a permeation tube. 
     
     
         7 . The system of  claim 6  wherein the sheath is a cylinder. 
     
     
         8 . The system of  claim 6  wherein the permeation tube contains Dichloromethane. 
     
     
         9 . The system of  claim 6  wherein the sheath is comprised of polyolefin. 
     
     
         10 . A method of improving the useful life of a permeation device, the method comprising the steps of:
 a) attaching a solid sheath assembly over a chemical emitting end of a permeation tube; and   b) heating, with a temperature in the range of 200 to 400 degrees Fahrenheit, the solid sheath assembly, the heating contracting the sheath assembly over the chemical emitting end of the permeation tube.   
     
     
         11 . The method of  claim 10  further including the step of using a solid sheath assembly comprising a body, distal shoulder, distal cap and proximal shoulder. 
     
     
         12 . The method of  claim 10  further including the step of using a liquid applied membrane to comprise the sheath assembly. 
     
     
         13 . The method of  claim 10  further including the step of using polyolefin to construct the sheath assembly. 
     
     
         14 . The method of  claim 10  further including the step of using a permeation tube containing Ammonia Crystal. 
     
     
         15 . The method of  claim 10  further including the step of using a permeation tube containing Dichloromethane.